[16a-Z16-1~11] 13.7 Compound and power electron devices and process technology

[16a-Z16-9] Analysis of mobility limitation factors in AlSiO/p-type GaN-based MOSFETs

〇Tetsuo Narita¹, Kenji Ito¹, Kazuyosi Tomita², Masahiro Horita², Daigo Kikuta¹ (1.Toyota CRDL., 2.Nagoya Univ.)

Keywords:power semiconductor device, MOSFET, channel mobility

For MOSFETs with or without an interfacial layer (IL) composed of a 3 nm-thick SiO₂, AlN or Al₂O₃, we investigate the correlation between the effective mobility extracted from the transconductance and the hysteresis in the transfer characteristic or the threshold voltage (V_t). The MOSFET with a SiO₂ IL exhibited the highest mobility around 60 cm²/Vs and the smallest hysteresis voltage, whereas MOSFETs without IL showed the lower mobility of 28 to 36 cm²/Vs. In addition, the mobility value tends to increase with decrease of V_t. These correlations can be explained by the electron trapping into the oxide border traps. This hypothesis was supported by the Hall-effect measurement under the gate bias.